This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Endothelial cells and different types of interstitial cells are cocultured within fibrin gels of different densities. The interstitial cells provide proangiogenic signals to the endothelial cells which respond by undergoing a process to form capillaries. This process can occur via two mechanisms, vasculogenesis or angiogenesis depending on the culture conditions. We are interested in the role of proteins which regulate the contractile nature of the cells or matrix degradation and what effects they have on the normal process of capillary morphogenesis.